package org.liuyuantao.thread.concurrent;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 在完成一组正在其他线程中执行的操作之前,它允许一个或多个线程一直等待
 * CountDownLatch可以接收多个线程的命令,也可以向多个线程发送命令
 */
public class CountdownLatchTest {

    public static void main(String[] args) {
        ExecutorService service = Executors.newCachedThreadPool();
        final CountDownLatch cdOrder = new CountDownLatch(1);
        final CountDownLatch cdAnswer = new CountDownLatch(3);
        for (int i = 0; i < 3; i++) {
            Runnable runnable = () -> {
                try {
                    System.out.println("线程" + Thread.currentThread().getName() +
                            "正准备接受命令");
                    cdOrder.await();
                    System.out.println("线程" + Thread.currentThread().getName() +
                            "已接受命令");
                    Thread.sleep((long) (Math.random() * 10000));
                    System.out.println("线程" + Thread.currentThread().getName() +
                            "回应命令处理结果");
                    cdAnswer.countDown();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            };
            service.execute(runnable);
        }
        try {
            Thread.sleep((long) (Math.random() * 10000));

            System.out.println("线程" + Thread.currentThread().getName() +
                    "即将发布命令");
            cdOrder.countDown();
            System.out.println("线程" + Thread.currentThread().getName() +
                    "已发送命令，正在等待结果");
            cdAnswer.await();
            System.out.println("线程" + Thread.currentThread().getName() +
                    "已收到所有响应结果");
        } catch (Exception e) {
            e.printStackTrace();
        }
        service.shutdown();

    }
}
